[Pw_forum] How to calculate Mean Square Displacement (MSD)

[Marzari Nicola]

?? For MSD you should not fold back.

Sent from a tiny keyboard... Contact info:
http://theossrv1.epfl.ch/Main/Contact

On 30 Oct 2017, at 09:19, Nam Tran <vnt981 at uowmail.edu.au<mailto:vnt981 at uowmail.edu.au>> wrote:


Dear Lorenzo and Pascal


Thank you so much for your kind replies.


Best Regards,

Nam Tran

________________________________
From: pw_forum-bounces at pwscf.org<mailto:pw_forum-bounces at pwscf.org> <pw_forum-bounces at pwscf.org<mailto:pw_forum-bounces at pwscf.org>> on behalf of Lorenzo Paulatto <paulatz at gmail.com<mailto:paulatz at gmail.com>>
Sent: Monday, October 30, 2017 7:10:17 PM
To: pw_forum at pwscf.org<mailto:pw_forum at pwscf.org>
Subject: Re: [Pw_forum] How to calculate Mean Square Displacement (MSD)

On 30/10/17 08:29, Nam Tran wrote:
> I do not know whether I should consider the distance with atom that goes
> about outside the box (a) or its image (b). Please check the image below

Usually the right thing is to consider the smallest of all the possible
distances. I.e. you put the red atom in all the positions which are
equivalent by periodic boundary conditions, these in principle are
infinite but going up to the second neighboring cell is usually more
than enough; for each case you take the distance with the blue atom, and
you take the minimum of all the distances.

kind regards


--
Lorenzo Paulatto - Paris
_______________________________________________
Pw_forum mailing list
Pw_forum at pwscf.org<mailto:Pw_forum at pwscf.org>
http://pwscf.org/mailman/listinfo/pw_forum
_______________________________________________
Pw_forum mailing list
Pw_forum at pwscf.org<mailto:Pw_forum at pwscf.org>
http://pwscf.org/mailman/listinfo/pw_forum
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20171030/13990773/attachment.html>